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February 3, 1858. 

 The President in the Chair. 



The President gave a brief account of a dissection of a 

 human foetus in the third week after conception, pointing 

 out some of the transitionary forms which are to be seen 

 only for a very short time, and comparing the various 

 parts with the corresponding parts of other animals. He 

 alluded to the position of the eyes, which are very far 

 upon the side of the head, and widely separated from 

 each other, corresponding to the permanent position of 

 those organs in cetaceans ; to the position and form of 

 the nostrils, which are far apart, and externally connected 

 with the cavity of the mouth, corresponding to the con- 

 dition of the nostrils in some of the American monkeys ; 

 to the branchial arches and fissures, opening into the 

 cavity of the oesophagus, and remaining a greater length 

 of time in some animals than in others, and persistent in 

 fishes, where they become the gills. He also pointed out 

 the position and earliest condition of the arms and legs, 

 remarking, that in all instances, even before any pressure 

 can be exerted upon them, both extremities assume the 

 angular form which persists in quadrupeds. The lower 

 extremities are not developed at the extreme termination 

 of the trunk; consequently the spinal canal projects and 

 gives the appearance of a tail, until the growth of the 

 legs is more advanced. The President also explained in 

 what manner an arrest of development would produce 

 some of the common malformations, such as hare-lip and 

 fissured palate, and instanced a case of fissure of the neck, 

 described by Hyrtl, where there was an opening from the 

 external surface into the gullet, one of the branchial fis- 

 sures of the embryo having remained unclosed. 



